Many types of input devices are presently available for performing operations in a computing system, such as buttons or keys, mice, trackballs, touch sensor panels, joysticks, touch screens and the like. Touch screens, in particular, are becoming increasingly popular because of their ease and versatility of operation as well as their declining price. Touch screens can include a touch sensor panel, which can be a clear panel with a touch-sensitive surface, and a display device that can be positioned behind the panel so that the touch-sensitive surface can substantially cover the viewable area of the display device. Touch screens can allow a user to perform various functions by touching the touch sensor panel using one or more fingers, a stylus or other object at a location dictated by a user interface (UI) being displayed by the display device. In general, touch screens can recognize a touch event and the position of the touch event on the touch sensor panel, and the computing system can then interpret the touch event in accordance with the display appearing at the time of the touch event, and thereafter can perform one or more actions based on the touch event.
The touch screen typically has a smooth touch-sensitive surface. As such, unlike standard keyboards that have physical buttons and keys that the user presses down to select, the UI virtual buttons and keys are selected merely by touching the touch screen at their displayed locations. As such, when a virtual button or key is touched, the user does not get the tactile feedback that pressing on the standard keyboard provides and must therefore watch the UI to ensure that the button or key was in fact touched.